1. Field
This invention pertains to backpacks and provides a coupling useful for adjusting the shoulder-to-hip length of such a frame.
2. State of the Art
Many common backpack frames of today have upstanding, spaced apart, side support members with structural means for holding the support members in their spaced apart condition. The side support members are approximately parallel and are inherently oriented approximately vertical when the frame is strapped to the back of an individual. In certain frames, the side support members are not quite parallel and may be somewhat closer spaced at either the upper or lower end of the frame. In any event, means are provided for attaching shoulder straps to the frame so that one strap may be brought over each shoulder of the user. Characteristically, one end of each strap is connected at a point above the midpoint of the frame and the other ends of the straps are connected to the frame below its midpoint, usually near its lower end.
Modern pack frames generally include a hip-belt or hip-strap arrangement whereby a portion of the load may be carried suspended from the hips. Such a hip-belt is usually connected to the frame either directly or by bracket means secured to the frame near the bottom of the frame.
Backpack frames are generally available in several sizes to provide a selection of frames for different body dimensions. Whatever the size of a particular frame, it is fixed in dimension with respect to both its width and vertical height. Selection of a properly sized frame is important because the frame, to be comfortable in use, must be dimensioned in correspondence to the distance between the shoulders and hips of the user.
A properly sized frame, when correctly affixed to the back of the user in general cervical alignment, should not extend so low that it interferes with the user's legs or positions the hip-belt below the user's hips. At the same time, it must not be so short as to place the hip-belt above the waist area and thus reduce the hip-belt's effectiveness. Shoulder straps which are used to suspend the frame on the back of the user are typically adjustable in length to allow for different shoulder-to-hip dimensions. However, only limited length adjustment of the shoulder straps is possible within the "comfort range" of the user. Straps of either too short or too great length are awkward and unpleasant in use. If the shoulder straps are adjusted to within the comfort range, the hip-belt will inherently be brought to an inappropriate level for users having longer or shorter torsos that those which match the frame. Of course, the torso length appropriate for a frame is also dependent on the girth of the user. There is thus a need for a simple device capable of providing for selective adjustment of the shoulder-to-hip dimensions of a backpack to accommodate users of different torso and girth dimensions.